• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.1
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• pp.51-59
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• 2012

The cold weather concrete poured in the winter season can cause the problem of the Due to recent high-rise building is made. In this research, the nominal mix of the early strength in concrete tried to be set through the mixing proportion experiment for each empirical variable and each component strength properties for the early strength improvement tries to be examined. In the cold weather concrete experiment, the cement and high early strength (type3) cement improving in OPC than OPC was excellent. The polycarboxylic acid based compound was exposed to be excellent in the intensity revelation properties. Because the using of the fly ash was disadvantageous it was excluded from this experiment. It showed the optimum temperature for the intensity revelation up over $12^{\circ}C$.

• Explosives and Blasting
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• v.22 no.3
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• pp.43-55
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• 2004

Use term of tower style construction exceeds recently. Accordingly, according to construction safety diagnosis result, achieve removal or Improvement construction. But when work removal, must shorten shut down time. Therefore, removal method of construction to use blasting demolition of construction is very profitable. Influence construction and equipment by blasting vibration and occurrence vibration caused by felling impact. Is using disadvantageous machine removal method of construction by and economic performance by effect of such vibartion. Therefore, this research studied techniques to forecast vibartion level happened at blasting demolition and vibration reduction techniques by use a scaled model test.

• Tunnel and Underground Space
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• v.8 no.2
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• pp.146-156
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• 1998

Nemerical algorithms were developed to analyze the behavior of the double lining as well as ground mass separately or simultaneously. A lining interface element was especially developed, verified and applied to the study on the coupled interaction of shotcrete and the concrete lining. It could be known fro parameter studys on double lining support systems that as the contact surface between shotcrete and concrete lining was rougher, the more decreased bearing capacity against the cracking of the system. If the thickness of the shotcrete increased, the bearing capacity of the double lining also increased linearly with the thickness. If the thickness of the concrete lining increased, the bearing capacity of the double lining had the relationship of the characteristic S-shape of a sigmoid function with the thickness. When the thickness increased over a given value, it was not useful to increase more the thickness because bearing capacity had no remarkable change. It could be concluded that the behavior of the shotcrete and concrete lining was generally reversed before and after the ratio of horizontal to vertical earth preassure of 1.0 and 0.5 respectively. Therefore, we could guess that the movement which two shotcrete and concrete lining deflect toward each other around the crown caused a friction between two linings and thus this disadvantageous effect could contribute to reducing the bearing capacity against the cracking.

• The Journal of Korea Robotics Society
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• v.12 no.4
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• pp.419-424
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• 2017

Twisted string actuators (TSAs) are tendon-driven actuators that provide high transmission ratios. Twisting a string reduces the length of the string and generates a linear motion of the actuators. In particular, TSAs have characteristic properties (compliance) that are advantageous for operations that need to interact with the external environment. This compliance has the advantage of being robust to disturbance in force control, but it is disadvantageous for precise control because the modeling is inaccurate. In fact, many previous studies have covered the TSA model, but the model is still inadequate to be applied to actual robot control. In this paper, we introduce a modified variable radius model of TASs and experimentally demonstrate that the modified variable radius model is correct compared to the conventional variable radius string model. In addition, the elastic characteristics of the TSAs are discussed along with the experimental results.

• Korean Journal of Clinical Laboratory Science
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• v.46 no.4
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• pp.140-142
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• 2014

To evaluate the recovery rates to increase toxigenic C. difficile, the selective enrichment broth culture methods were compared with commonly used cytotoxin assays and toxigenic culture. First, the enrichment culture, using the selective medium broth for 2 to 5 days, was performed and then, toxigenic C. difficile was confirmed by C. difficile toxin gene-specific PCR after being cultured on C. difficile selective agar. The sensitivity of C. difficile from the enrichment culture (100%) was higher than that of C. difficile selective agar culture (93.8%), while positive predictive values (PPV) were low; 72.7% (16/22) and 88.2% (15/17). PPV of the enrichment culture are not high. Recently, combinations of C. difficile selective agar culture, C. difficile A & B assays, glutamate dehydrogenase, and nucleic acid amplification method are widely used. The enrichment culture was disadvantageous in PPV, turn-around time, and cost. So, what we performed is not considered as a common method of diagnosis of C. difficile-associated diarrhea.

• Journal of the Korean Operations Research and Management Science Society
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• v.29 no.2
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• pp.19-43
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• 2004

This study was motivated by a practical need for estimating the macroeconomic effect of government IT Promotion investment, specifically for micro and small firms. Small firms have been in a disadvantageous position to adopt and utilize new IT compared with medium or large-sized firms. Small firms don't have enough resource to acquire IT in general, therefore private IT companies don't have much incentive to develop IT services and products for small firms. Lack of feasible IT solutions for small firms again restricted active IT adoption of small firms. Government recognized the vicious cycle, therefore decided to promote private IT companies to develop IT services and products for small firms's. Our main concern was to identify a relevant government supporting Policy, especially in the amount and the period. To do this, we first constructed a system dynamics simulation model to Investigate important factors and causal relationships among them. Simulation results showed 2.19% of GDP contribution and 0.16% of employment contribution in max from small firms' IT adoption. Also we could find that investing proper amount for a short period would be for better than maintaining Investing small amount for a long period.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.39
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• pp.25.1-25.6
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• 2017

Background: The conventional transcervical resection for submandibular gland disease has some risks and an unsatisfactory cosmetic result. Recently, robot-assisted surgery has been developed as a plausible substitute for conventional surgery which provides an excellent cosmetic outcome. Case presentation: The authors performed robot-assisted sialadenectomy via modified facelift incision using the da Vinci Xi surgical system (Intuitive Surgical Inc., CA, USA) with two endowrist arms (monopolar curved scissors and Maryland bipolar forceps) successfully in a 44-year-old female patient who suffered from sialolith and severe atrophic submandibular gland. Conclusions: If similar studies are done in the future, this robot-assisted sialadenectomy may become established as an alternative to existing disadvantageous surgical methods.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.4
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• pp.350-353
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• 2004

The integral reactor is tripped by the boron injection to the reactor when the CEA(Control element assembly) is not available due to its malfunction. In general, the borated water is made by dissolving the boron powder in the water and is stored in a tank. and then injected. But, this method is disadvantageous from the view point of construction cost, operation and maintenance because it has many components and is complicated. In this study, the boron powder direct vessel injection method is adopted to improve the system. Injecting the boron powder directly to the vessel and decreasing of number of components, the system configuration, operation and maintenance is simplified and the construction cost is reduced.

• Journal of the Korea Institute of Building Construction
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• v.3 no.2
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• pp.149-156
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• 2003

The purpose of this study was to find out the most reasonable design in the superstructure of an underground parking lot which needs to be considered with the economic efficiency being influenced on the subdivision price, construction duration, workability and the maintenance of crack and leakage status of apartment house. In this research, we've evaluated the fitness for the superstructure of an underground parking lot by examination of construction constraint, which was based on the calculated data of structural design and quantity survey. The results of this study are summarized as follows. 1. The system of the absent structure of beam is proper structure for economic efficiency, construction duration and workability, but it is disadvantageous at the side of maintenance efficiency because of the many part of large slab. In the opposite direction, the establishing structure of beam has the advantages of structural stability except economic efficiency, construction duration and workability 2. It's required a proper selection for the views being contrary to each other which the owners considers good quality, on the other hand, the contractors consider construction duration and workability. 3. In making a selection for the superstructure of an underground parking lot, we have concluded that it is the most important to choose the proper structure for the demanded performance by contrasting with two system. (2Bay or 3Bay)

• Journal of the Korean Society for Precision Engineering
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• v.33 no.5
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• pp.419-425
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• 2016

A powder spreading phenomenon is one of disadvantageous characteristics of the powder bed fusion process using electron beams. The powder spreading phenomenon can be controlled using a pre-heating process of metallic powders. The aim of this paper was to investigate the preheating process of Stellite21 powder using electron beams. Powder spreading experiments were performed to examine the influence of process parameters on the spreading behaviors of Stellite21 powder. Powder heating experiments were carried to investigate the effects of the focusing current of the electron beam on the quality of the heated region. Using the results of the powder spreading and heating experiments, an appropriate combination of process parameters was obtained. The pre-heating experiment of Stellite21 was performed using the estimated combination of process parameters. The results of preheating experiments showed that the preheated Stelllite21 layer with desired characteristics can be created when the estimated combination of process parameters is applied.